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The future of agriculture is at stake as soil health continues to degrade. Practices like monoculture, plowing, and overuse of chemical inputs have depleted soil nutrients and structure, prompting farmers to explore alternative soil management strategies. While upscaling these solutions shows promise, policy, and financial support remain insufficient.
‘If agriculture is a body, soil is its soul’. Soil health is the cornerstone of sustainable agriculture, influencing food security, water regulation, and ecosystem resilience. In East Africa, soil degradation is driven by unsustainable farming practices, deforestation, and over-reliance on chemical inputs. This has resulted in severe soil erosion, nutrient depletion, and declining agricultural productivity. The Green Revolution initially boosted crop yields in the region through chemical fertilisers, but their overuse has led to nutrient imbalances, soil acidification, and reduced microbial activity. Studies in Kenya’s Rift Valley show continuous nitrogen fertiliser application depletes soil fertility and increases nitrate leaching into water sources.
Healthy soils encompass nutrient availability, structure, organic matter, water retention, and microbial activity. Unlike chemical fertilisers that focus on single-nutrient supplementation, alternatives aim to enhance overall soil fertility and microbial diversity, ensuring long-term soil vitality with minimum cost. Smallholder farmers mostly use compost, green manure, and compost tea to enrich the soil. Compost, derived from decomposed organic waste, improves nutrient content, microbial activity, and water retention. Green manure, such as cover crops like clover and cowpeas, protects soil from sun exposure and boosts organic matter and nitrogen. In Kenya, green manure has been shown to increase maize yield by up to 25 percent. Compost tea, a liquid extract of compost, introduces beneficial microbes directly to the soil.
Biofertilisers play a crucial role in sustainable agriculture. Rhizobia converts atmospheric nitrogen into plant-usable forms, while mycorrhizal inoculants enhance nutrient and water uptake. These microbes also contribute to soil structure by producing glomalin, a glycoprotein that binds soil particles. In Tanzania, applying biofertilisers has led to 30 percent higher legume yields. Biochar, a stable, charcoal-like material produced by burning organic matter in low-oxygen conditions, reduces acidity, retains moisture and nutrients and supports beneficial soil microorganisms.
Farmers in East Africa are also increasingly using black soldier fly (BSF) compost and vermicompost as sustainable alternatives. BSF larvae convert organic waste into nutrient-rich frass, enhancing soil fertility and increasing maize yields. Vermicomposting uses earthworms to break down organic matter into nutrient-rich compost. The saying ‘fertiliser feeds the plant, while vermicompost feeds the soil’ highlights its holistic benefits.
Organic fertiliser has many benefits beyond
improving soil health
Jeevamruth, a fermented cost-effective biofertiliser, provides nutrients and beneficial microbes to the soil. It improves soil structure, water retention, and nutrient availability. Though the use of jeevamrut in East Africa is still limited, it is gaining popularity due to its affordability and ease of production. A similar biofertiliser, bokashi, has been used by smallholder farmers to restore degraded soils in Kenya’s Tharaka Nithi County.
Rice husk ash, rich in silica and potassium, improves aeration and root penetration, while seaweed extracts, containing micronutrients and bioactive compounds, stimulate plant immunity. Rock dust, sourced from natural rock formations, enhances soil fertility by slowly releasing essential minerals like magnesium, calcium, and silicon. It also improves soil texture, aeration, and microbial activity, supporting nutrient cycling and organic matter decomposition.
A supportive policy environment is essential for the successful adoption of alternatives. The Kenyan Agricultural Soil Fertility Policy, introduced in 2023, marks a promising step forward. It explicitly recognises Kenya’s soil degradation challenges and emphasises the use of biofertilisers as a core element of the mitigation strategy. The policy outlines the government’s key responsibilities, including the development of a regulatory framework for biofertilisers, supporting capacity-building programs for their effective use in soil management, and strengthening institutional support to develop a robust value chain that ensures biofertilisers' availability.
Farmers using already various alternatives for soil
health management. Policies and investments need to
support the availability of these fertilisers and science
need to optimize their efficiency
Alternative effective soil inputs accessible to farmers at low costs should be integrated into resilient agricultural systems. Agroforestry and strategies like intercropping and crop rotation combine plants with different nutrient needs and enhance soil fertility and ecosystem balance. By embracing both innovative and traditional practices, farmers in East Africa can revitalize degraded soils, increase productivity, and support environmental conservation. Scaling these solutions requires strong policy support, improved resource availability, and strengthened value chains. With collective efforts, these approaches can transform agriculture, ensuring food security and sustainability for future generations.
This article was published as part of the Soil Atlas Kenya Edition 2025. You can download a copy here